feat: Allow specifing how object data is encoded

Adds a --data-encoding flag to `ipfs object get` to let the user
specify base64 encoding for object data.

License: MIT
Signed-off-by: Alex Potsides <alex@achingbrain.net>

core/commands/object/object.go

@@ -204,12 +204,23 @@ This command outputs data in the following encodings:
   * "protobuf"
   * "json"
   * "xml"
-(Specified by the "--encoding" or "--enc" flag)`,
+(Specified by the "--encoding" or "--enc" flag)
+
+The encoding of the object's data field can be specifed by using the
+--data-encoding flag
+
+Supported values are:
+	* "text" (default)
+	* "base64"
+`,
 	},
 
 	Arguments: []cmdkit.Argument{
 		cmdkit.StringArg("key", true, false, "Key of the object to retrieve, in base58-encoded multihash format.").EnableStdin(),
 	},
+	Options: []cmdkit.Option{
+		cmdkit.StringOption("data-encoding", "Encoding type of the data field, either \"text\" or \"base64\".").WithDefault("text"),
+	},
 	Run: func(req oldcmds.Request, res oldcmds.Response) {
 		n, err := req.InvocContext().GetNode()
 		if err != nil {
@@ -219,6 +230,12 @@ This command outputs data in the following encodings:
 
 		fpath := path.Path(req.Arguments()[0])
 
+		datafieldenc, _, err := req.Option("data-encoding").String()
+		if err != nil {
+			res.SetError(err, cmdkit.ErrNormal)
+			return
+		}
+
 		object, err := core.Resolve(req.Context(), n.Namesys, n.Resolver, fpath)
 		if err != nil {
 			res.SetError(err, cmdkit.ErrNormal)
@@ -231,9 +248,15 @@ This command outputs data in the following encodings:
 			return
 		}
 
+		data, err := encodeData(pbo.Data(), datafieldenc)
+		if err != nil {
+			res.SetError(err, cmdkit.ErrNormal)
+			return
+		}
+
 		node := &Node{
 			Links: make([]Link, len(object.Links())),
-			Data:  string(pbo.Data()),
+			Data:  data,
 		}
 
 		for i, link := range object.Links() {
@@ -702,3 +725,14 @@ func unwrapOutput(i interface{}) (interface{}, error) {
 
 	return <-ch, nil
 }
+
+func encodeData(data []byte, encoding string) (string, error) {
+	switch encoding {
+	case "text":
+		return string(data), nil
+	case "base64":
+		return base64.StdEncoding.EncodeToString(data), nil
+	}
+
+	return "", fmt.Errorf("unkown data field encoding")
+}

test/sharness/t0051-object.sh

@@ -47,6 +47,23 @@ test_object_cmd() {
     test_cmp ../t0051-object-data/expected_getOut actual_getOut
   '
 
+  test_expect_success "'ipfs object get' can specify data encoding as base64" '
+    ipfs object get --data-encoding base64 $HASH > obj_out &&
+    echo "{\"Links\":[],\"Data\":\"CAISCkhlbGxvIE1hcnMYCg==\"}" > obj_exp &&
+    test_cmp obj_out obj_exp
+  '
+
+  test_expect_success "'ipfs object get' can specify data encoding as text" '
+    echo "{\"Links\":[],\"Data\":\"Hello Mars\"}" | ipfs object put &&
+    ipfs object get --data-encoding text QmS3hVY6eYrMQ6L22agwrx3YHBEsc3LJxVXCtyQHqRBukH > obj_out &&
+    echo "{\"Links\":[],\"Data\":\"Hello Mars\"}" > obj_exp &&
+    test_cmp obj_out obj_exp
+  '
+
+  test_expect_failure "'ipfs object get' requires known data encoding" '
+    ipfs object get --data-encoding nonsensical-encoding $HASH
+  '
+
   test_expect_success "'ipfs object stat' succeeds" '
     ipfs object stat $HASH >actual_stat
   '